MBP 13 inch (mid 2010) IOS 10.9.1 Mavericks 2.66 GHz Intel Core 2 Duo 8 GB 1067 MHz DDR3. So here's the problem: I'm working away in Pages or Numbers and I suddenly get a message saying 'this document could not be auto saved' and I lose whatever I was doing since reopening the document. Other applications just stop working whilst I'm working in them and I have to resort to holding down the power button in order to turn the machine off because I can't do anything else. I can't force close, shut down, restart etc. (After restarting machine I can then use re start, shut down etc). So I start working again and same thing happens all over again. I do notice that when I reboot the screen is white, the gear whirs away, then the screen goes grey, the cursor arrow automatically goes up to the top left corner of the screen for a few seconds before the desktop reveals itself and I can't remember if this is what it normally does. Here's a list of what I've done: Verified disk First aided disk Erased disk Reinstalled OS Started in safe mode Reset NVRAM Upgraded HDD to 500GB Installed Mavericks Used safe mode Booted from recovery Reinstalled Mavericks Reset SMC Whilst I'm in an application everything operates quickly and smoothly and then all of a sudden stops. I'm hoping one of you clever technicians have seen this type of behaviour before and can offer me some advice. Thank you in advance.